EXPANSION OF IRON AT THE MOMENT OF SOLIDIFICATION.
The question of iron expanding at the moment of solidification was, up to about the year 1897, affirmed by some and questioned by others. It remained for Mr. John R. Whitney, of Philadelphia, Pa., to first demonstrate in a practical way that iron truly expanded at the moment of solidification. This was fully verified by the author in experiments which he conducted immediately after Mr. Whitney published his results in the National Car and Locomotive Builder of May, 1889, of which the following is an extract, and by later experiments shown on pages 384, 387 and 424:
On a more recent occasion the following experiment was made with an apparatus more carefully prepared, as shown, Fig. 72. A pattern, A, 4 feet long, 3^ inches deep and 2^ inches wide, was moulded in open sand; one end of the mould being- closed by fire brick B, and the other end by a piece of gas carbon D, which was suitably connected with a small battery and galvanometer. The fire brick B rested at one end against a block of iron C, weighing about half a ton. The gas carbon block D was carefully secured in the sand, so that the
FIG. 72.1 0.091 0085 0.31 0-33 1.32 1.32 0.046 0.047